Valves often develop leaks as they age. Leaking valves can be annoying, wasteful, and can cause damage in residential settings, but can be far more problematic in industrial applications. Factory lines may need to be shut down to repack or replace valves, resulting in lost production and unnecessary downtime. Leaks can cause environmental damage and safety issues. Steam leaks can scald and even kill workers. The Environmental Protection Agency (EPA) is concerned about pollution resulting from leaky valve stem seals in factories and oil fields. In extreme cases, such as semiconductor manufacturing, even microscopic leaks can be fatal—breathing tanks and hazmat suits are often required to clean up after leaks are detected in semiconductor foundries.
Most traditional valves have two moving seals: (1) the “seat” where the flow of material through the valve is allowed, controlled, and shut off, and (2) the “stem seal” that keeps the material from leaking out of the hole for the valve handle. Studies have shown that up to 80 percent of the leaks encountered in real world valves are associated with the stem seals because they tend to entrain dirt and grit which can erode the mating surfaces over time.
Traditional valves contain stem seals that often degrade or leak over time. Previous seal-less valves often employed bending or flexing components such as bellows or membranes that can degrade or fatigue and also leak over long periods of use. Additionally, previous generations of magnetically-actuated valves (sometimes referred to herein as magnetic valves) often include internal magnets and/or operated in a linear solenoid type manner making high temperature operation difficult to achieve, and often requiring continuous power to maintain their position. Previous manual override systems for magnetic valves include dynamic seals that may leak even when the valve was being operated magnetically.
Some industries, such as the petrochemical industry would be very reluctant to accept magnetic valve actuators without a provision to be able to break free a stuck valve in an emergency situation. With traditional valves, the device employed to “unstick” valves is referred to as a “cheater handle” and it is essentially a spanner or wrench like device that attaches over the regular handle to increase the torque applied to the valve. Increased torque is usually due to a longer cheater handle or a cheater handle that allows greater leverage relative to the original valve handle. Typically, cheater handles are only used to break free a badly corroded or stuck valve that hasn't been actuated in a long time. Cheater handles are not typically employed in day-to-day operation.
Magnetic valves have a set torque limit that cannot be increased by simple measures such as attaching a longer lever or handle. This is normally a design feature because it may be desirable to limit the closing torque available from the magnetic valve coupling to protect the valve seat from over-tightening, but unfortunately the valve may become stuck after having been left in one position for an extended period of time, or when handling sticky or corrosive substances. There are various methods available to deal with this dilemma such as those described by Davis in U.S. Pat. Nos. 9,797,521 and 10,151,403, but in instances where these magnetic techniques are insufficient, it may be desirable to employ a traditional mechanical cheater handle such as described in Ruyak's U.S. Pat. Nos. 4,284,262 and 4,372,892.
Other manual override mechanisms such as Ruyak's tend to rely on dynamic seals that are exposed to the outside environment and may degrade over time negating the original advantages of the magnetic valve topology.